>>>>> "Duncan" == Duncan <1i5t5.duncan@xxxxxxx> writes:
Duncan> OTOH, certain high-performance hardware goes beyond the current
Duncan> standard and does a queued trim, without forcing a flush of the
Duncan> queue in the process. But this hardware tends to be rather rare
Duncan> and expensive,
Queued trim has started to appear in consumer SSDs. However, since we're
the only OS that supports it the feature has come off to a bumpy start.
We tried to enable it on a drive model that passed testing here but we
had to revert to unqueued when bug reports started rolling in this week.
Duncan> (FWIW, in new enough versions of smartctl, smartctl -i will have
Duncan> a "SATA Version is:" line, but even my newer Corsair Neutrons
Duncan> report only SATA 2.5, so obviously they don't support queued
Duncan> trim by the standard, tho it's still possible they implement it
Duncan> beyond the standard, I simply don't know.)
The reported SATA version is in no way indicative of whether a drive
supports queued trim. The capability flag was put a highly unusual place
in the protocol. I posted a patch that makes this information available
in sysfs a while back. However, the patch is currently being reworked to
support a debug override...
Until then, the following command will give you the answer:
# smartctl -l gplog,0x13 /dev/sda | grep 0000:
0000000: 01 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 |................|
^^ ^^
These two 01 fields indicate that the drive supports queued trim.
--
Martin K. Petersen Oracle Linux Engineering
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